Methods and associated apparatus for downhole data retrieval, monitoring and tool actuation

ABSTRACT

A system of downhole communication and control is provided in methods and associated apparatus for data retrieval, monitoring and tool actuation. In a described embodiment, an item of equipment installed in a tubular string has a first communication device associated therewith. A tool conveyed into the tubular string has a second communication device therein. Communication is established between the first and second devices. Such communication may be utilized to control operation of the tool, retrieve status information regarding the item of equipment, supply power to the first device and/or identify the item of equipment to the tool.

BACKGROUND OF THE INVENTION

[0001] The present invention relates generally to operations performedin conjunction with a subterranean well and, in an embodiment describedherein, more particularly provides a method and apparatus for downholeretrieval of data, monitoring and tool actuation.

[0002] It is usually the case that a tubular string is installed in asubterranean well with one or more items of equipment interconnected inthe tubular string. Thereafter, a tool conveyed into the tubular stringmay be positioned relative to the item of equipment, engaged with theitem of equipment and/or utilized to actuate the item of equipment, etc.

[0003] In the past, various mechanisms and methods have been utilizedfor positioning a tool relative to an item of equipment in a tubularstring, for engaging the tool with the item of equipment and forutilizing the tool to actuate the item of equipment. For example, wherethe item of equipment is a sliding sleeve-type valve, a shifting tool istypically conveyed on wireline, slickline or coiled tubing into thevalve and engaged with the sliding sleeve. An operator is aware that theshifting tool is properly positioned relative to the valve due to theengagement therebetween, as confirmed by the application of force to theshifting tool. The shifting tool may be configured so that itoperatively engages only the desired sliding sleeve, out of multipleitems of equipment installed in the tubular string, by equipping theshifting tool with a particular set of keys or lugs designed to engageonly a particular profile formed in the desired sliding sleeve.

[0004] Unfortunately, it is often the case that the operator is not ableto positively determine whether the shifting tool is properly engagedwith the desired sliding sleeve, such as when the well is highlydeviated. Additionally, the operator may not accurately know informationwhich would aid in performance of the task of shifting the sleeve. Forexample, the operator might not know that an excessive pressuredifferential exists across the sleeve, or the operator might attempt toshift the sleeve to its fully open position not knowing that this shouldnot be done with an excessive pressure differential across the sleeve.Thus, it may be clearly seen that improved methods of positioning,engaging and actuating tools are needed.

[0005] Many operations in wells would be enhanced if communication werepermitted between an item of equipment installed in a tubular string anda tool conveyed into the string. For example, if a valve was able tocommunicate its identity to a shifting tool, an accurate determinationcould be made as to whether the tool should be engaged with the valve.If a valve was able to communicate to the tool data indicative ofpressure applied to a closure member of the valve, such as a slidingsleeve, a determination could be made as to whether the tool shoulddisplace the closure member, or to what position the closure membershould be displaced.

[0006] Improved communication methods would also permit monitoring ofitems of equipment in a well. In one application, a tool conveyed into atubular string could collect data relating to the status of variousitems of equipment installed in the tubular string. It would bedesirable, for example, to be able to monitor the status of a packerseal element in order to determine its remaining useful service life, orto be able to monitor the strain, pressure, etc. applied to a portion ofthe tubular string, etc.

[0007] Therefore, from the foregoing, it may be seen that it would behighly advantageous to provide improved methods and apparatus fordownhole data retrieval, monitoring and tool actuation.

SUMMARY OF THE INVENTION

[0008] In carrying out the principles of the present invention, inaccordance with an embodiment thereof, a system for facilitatingdownhole communication between an item of equipment installed in atubular string and a tool conveyed into the tubular string is provided.Associated methods of facilitating such downhole communication are alsoprovided, as well as applications in which the downhole communication isutilized for data retrieval, monitoring and tool actuation.

[0009] In one aspect of the present invention, the downholecommunication system includes a first communication device associatedwith the item of equipment and a second communication device included inthe tool. Communication may be established between the devices when thedevice in the tool is brought into sufficiently close proximity to thedevice associated with the item of equipment.

[0010] In another aspect of the present invention, the tool suppliespower to the first device. Such provision of power by the tool mayenable the first device to communicate with the second device. In thismanner, the first device does not need to be continuously powered. Thefirst device may, however, be maintained in a dormant state and thenactivated to an active state by the tool.

[0011] In yet another aspect of the present invention, the communicationbetween the first and second devices may be by any of a variety ofmeans. For example, electromagnetic waves, inductive coupling, pressurepulses, direct electrical contact, etc. may be used. The communicationmeans may also be the means by which power is supplied to the firstdevice.

[0012] In still another aspect of the present invention, communicationbetween the devices may be used to control operation of the tool. Forexample, where the item of equipment is a valve and the tool is ashifting tool for displacing a closure member of the valve,communication between the first and second devices may be used todetermine whether an excessive pressure differential exists across theclosure member. This determination may then be utilized to control thedisplacement of the closure member by the tool. As another example, thetool may not be permitted to engage the item of equipment until thecommunication between the devices indicates that the tool isappropriately positioned relative to the item of equipment.

[0013] In yet another aspect of the present invention, communicationbetween the devices may be used to monitor a status of the item ofequipment. For example, the first device may be connected to a sensor,such as a pressure sensor, a strain gauge, a hardness sensor, a positionsensor, etc., and may transmit data regarding the status to the seconddevice.

[0014] These and other features, advantages, benefits and objects of thepresent invention will become apparent to one of ordinary skill in theart upon careful consideration of the detailed description ofrepresentative embodiments of the invention hereinbelow and theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1 is a schematic partially cross-sectional view of a firstapparatus and method embodying principles of the present invention;

[0016]FIG. 2 is a schematic partially cross-sectional view of a secondapparatus and method embodying principles of the present invention;

[0017]FIG. 3 is a schematic partially cross-sectional view of a thirdapparatus and method embodying principles of the present invention;

[0018]FIG. 4 is a schematic partially cross-sectional view of a fourthapparatus and method embodying principles of the present invention;

[0019]FIGS. 5A&B are schematic partially cross-sectional views of afifth apparatus and method embodying principles of the presentinvention;

[0020]FIG. 6 is a schematic partially cross-sectional view of a sixthapparatus and method embodying principles of the present invention;

[0021]FIG. 7 is an enlarged scale schematic partially cross-sectionalview of a portion of the sixth apparatus of FIG. 6; and

[0022]FIG. 8 is a schematic partially cross-sectional view of a seventhapparatus and method embodying principles of the present invention.

DETAILED DESCRIPTION

[0023] Representatively and schematically illustrated in FIG. 1 is amethod 10 which embodies principles of the present invention. In thefollowing description of the method 10 and other apparatus and methodsdescribed herein, directional terms, such as “above”, “below”, “upper”,“lower”, etc., are used for convenience in referring to the accompanyingdrawings. Additionally, it is to be understood that the variousembodiments of the present invention described herein may be utilized invarious orientations, such as inclined, inverted, horizontal, vertical,etc., without departing from the principles of the present invention.

[0024] In the method 10, a service tool 12 is conveyed into a tubularstring 14 and engaged with an item of equipment or valve 16interconnected in the string. As representatively illustrated in FIG. 1,the valve 16 is a sliding sleeve-type valve and the tool 12 is utilizedto displace a closure member or sleeve 18 of the valve relative to ahousing 20 of the valve to thereby permit or prevent fluid flow throughone or more openings 22 formed through a sidewall of the housing.However, it is to be clearly understood that a method incorporatingprinciples of the present invention may be performed with other items ofequipment and other types of valves, and with other types of servicetools.

[0025] The sleeve 18 of the representatively illustrated valve 16 hasthree positions relative to the housing 20. In the closed position ofthe sleeve 18 as depicted in FIG. 1, the sleeve completely preventsfluid flow through the opening 22. If the sleeve 18 is displacedupwardly until a relatively small diameter opening 24 formed through asidewall of the sleeve is aligned with the opening 22 in the housing 20,the sleeve is in an equalizing position in which limited fluid flow ispermitted through the opening 22. The equalizing position of the sleeve18 is typically utilized in this type of valve when there is anexcessive pressure differential across the sleeve and it is desired toreduce this pressure differential without eroding or damaging sealsresisting the pressure differential. If the sleeve 18 is displacedfurther upwardly until another opening 26 formed through the sleevesidewall is aligned with the opening 22 in the housing 20, the sleeve isin an open position in which relatively unrestricted fluid flow ispermitted through the opening 22. Of course, it is not necessary inkeeping with the principles of the present invention for a valve orother item of equipment to have the positions representatively describedabove and depicted in FIG. 1.

[0026] The tool 12 is utilized to displace the sleeve 18 between theclosed, equalizing and open positions as needed to control fluid flowthrough the opening 22. In order to secure the tool 12 relative to thehousing 20, the tool is provided with one or more engagement members,lugs, dogs or keys 28 configured for cooperative engagement with aprofile 30 internally formed in the housing. Other means of securing thetool 12 relative to the valve 16, other types of engagement members andother types of profiles may be utilized in the method 10, withoutdeparting from the principles of the present invention.

[0027] The tool 12 also includes engagement members or dogs 32 forengaging the sleeve 18. The dogs 32 permit application of an upwardly ordownwardly directed force from the tool 12 to the sleeve 18 fordisplacement of the sleeve upwardly or downwardly relative to thehousing 20. Of course, if in an alternate embodiment a closure member ofa valve is displaced radially, rotationally, laterally or otherwise,corresponding changes to the tool 12 may be made in keeping with theprinciples of the present invention. Additionally, differentlyconfigured, numbered, arranged, etc., engagement members may be used toprovide engagement between the tool 12 and the sleeve 18 and/or housing20.

[0028] The dogs 32 extend outwardly from a housing 34 which is attachedto an actuator 36 of the tool 12. As representatively described herein,the actuator 36 is a linear actuator, since the sleeve 18 is linearlydisplaced between its positions relative to the housing 20, however, itis to be clearly understood that other types of actuators may beutilized, without departing from the principles of the presentinvention. An acceptable actuator which may be used for the actuator 36is the DPU (Downhole Power Unit) available from Halliburton EnergyServices, Inc.

[0029] The DPU is especially adapted for conveyance by slickline orcoiled tubing, since it is battery-powered. A slickline 46 is depictedin FIG. 1 as the means used to convey the tool 12 in the string 14. Itshould be noted, however, that otherwise powered actuators and othermeans of conveying a tool within a string may be utilized, withoutdeparting from the principles of the present invention.

[0030] The valve 16 includes communication devices 38, 40 which permitcommunication between the valve and respective communication devices 42,44 of the tool 12. The communication devices 38, 40, 42, 44 may servemany purposes in the interaction of the tool 12 with the valve 16, andmany of these are described below. However, the descriptions of specificpurposes for the communication devices 38, 40, 42, 44 in therepresentatively illustrated method 10 are not to be taken as limitingthe variety of uses for communication devices in a method incorporatingprinciples of the present invention.

[0031] The device 38 may be supplied with power by a battery or otherpower source 39. The power source 39 may be included in the valve 16, orit may be remote therefrom. It is to be clearly understood that anymeans of supplying power to the device 38 may be utilized, withoutdeparting from the principles of the present invention. The power source39 may also supply power to sensors, etc. associated with the device 38.

[0032] The device 38 may communicate to the device 42 the identity ofthe valve 16 (e.g., a digital address of the valve), so that adetermination may be made as to whether the tool 12 is positionedrelative to the proper item of equipment in the string 14. The string 14may include multiple items of equipment, and this communication betweenthe devices 38, 42 may be used to select the valve 16 from among themultiple items of equipment for operation of the tool 12 therewith. Forexample, the device 38 may continuously transmit a signal indicative ofthe identity of the valve 16 so that, as the tool 12 is conveyed throughthe string 14, the device 42 will receive the signal when the devices38, 42 are in sufficiently close proximity to each other.

[0033] As another example, the device 38 may not transmit a signal untilthe device 42 polls the device 38 by transmitting a signal as the tool12 is conveved through the string 14. The tool 12 may be programmed totransmit a signal to which only the device 38, out of multiple suchdevices of respective other items of equipment installed in the string14, will respond. Such programming may be accomplished, for example, byutilizing an electronic circuit 48 connected to the device 42 in thetool 12 or, if the tool 12 is in communication with a remote location,for example, via wireline or other data transmission means, theprogramming may be accomplished remote from the tool. Theabove-described methods of identifying an item of equipment to a servicetool, and of selecting from among multiple items of equipment installedin a tubular string for operation of a tool therewith, may be utilizedwith any of the methods described herein.

[0034] Transmission of a signal from the device 42 to the device 38 mayactivate the device 38 from a dormant state, in which the device 38consumes very little power, to an active state, in which more power isconsumed by the device 38 as it communicates with the device 42. Suchactivation of the device 38 may permit the device 38 to communicate withthe device 42.

[0035] As another alternative, the tool 12 may supply power to operatethe device 38. Thus, the device 38 may not communicate with the device42 until the tool 12 is in sufficiently close proximity to the valve 16,or is in an operative position relative to the valve. Methods ofsupplying power from the tool 12 to operate the device 38 are describedbelow. However, it is to be clearly understood that other methods may beutilized, without departing from the principles of the presentinvention.

[0036] Another purpose which may be served by the communication betweenthe devices 42, 38 is to provide an indication that the tool 12 isoperatively positioned, or at least within a predetermined distance ofan operative position, relative to the valve 16. For example,communication between the devices 38, 42 may indicate that theengagement member 28 is aligned with the profile 30. The tool 12 may beprevented from extending the engagement member 28 outwardly intoengagement with the profile 30 until the communication between thedevices 38, 42 indicates such alignment. This indication may betransmitted by the tool 12 to a remote location, for example, so that anoperator may confirm that the tool 12 has operatively engaged the valve16.

[0037] Yet another purpose which may be served by the communicationbetween the devices 38, 42 is to indicate the position of the sleeve 18relative to the housing 20. As representatively illustrated in FIG. 1,one or more position sensors 50, such as hall effect devices or adisplacement transducer, etc., may be connected to the device 38, sothat the device may transmit data indicative of the sleeve 18 positionto the device 42. This indication may then be transmitted by the tool 12to a remote location, for example, so that an operator may confirm thesleeve 18 position.

[0038] Note that one or more of the sensors 50 may be any type ofsensor. For example, one of the sensors 50 may be a pressure ortemperature sensor. Use of one of the sensors 50 as a pressure indicatormay be useful in determining pressure applied to, or a pressuredifferential across, the sleeve 18.

[0039] Another sensor 51 is positioned proximate at least one of theopenings 22, and may be in contact with fluid flowing through theopening. The sensor 51 is connected to the device 38 for transmission ofdata from the sensor to the device. The sensor 51 may be a resistivity,capacitance, inductance and/or particle sensor for detecting theseproperties of fluid flowing through the opening 22. For example, thesensor 51 may be utilized to determine a percentage of water in thefluid flowing through the opening 22, to determine the number and/orsize of particles flowing through the opening 22, etc.

[0040] The devices 40, 44 communicate by direct electrical contacttherebetween. As depicted in FIG. 1, the device 40 is connected to apressure sensor 52 exposed to fluid pressure on the exterior of thehousing 20. In conjunction with another pressure sensor, such as one ofthe sensors 50 or another pressure sensor 54, exposed to fluid pressurein the interior of the housing 20, the pressure differential across thesleeve 18 may be readily determined. Such determination may be made byan electronic circuit 56 of the tool 12, transmitted from the tool to aremote location and/or the determination may be made at the remotelocation from a transmission of the interior and exterior pressureindications.

[0041] As with the devices 38, 42 described above, communication betweenthe devices 40, 44 may be used for many purposes, in addition to that ofsensor data communication. For example, communication between thedevices 40, 44 may be used to indicate that the tool 12 is operativelypositioned relative to the valve 16. Since the representativelyillustrated devices 40, 44 communicate by direct electrical contact,such communication between the devices indicates at least that thedevices are aligned with each other. This indication may be transmittedby the tool 12 to a remote location. This indication may also be used tocontrol extension of the dogs 32 outwardly from the housing 34 intoengagement with the sleeve 18 by the tool 12 in a manner similar to thatdescribed above for control of extension of the keys 28. An indicationthat the keys 28 and/or dogs 32 have operatively engaged the respectivehousing 20 and/or sleeve 18 may also be transmitted by the tool 12 to aremote location.

[0042] As another example, the circuit 56, or another circuit at aremote location, may be programmed to control operation of the tool 12based at least in part on data communicated between the devices 40, 44.The circuit 56 may be connected to the actuator 36 and may be programmedto prevent the actuator from displacing the sleeve 18 to the openposition if the sensors 52, 54 indicate that the pressure differentialacross the sleeve is outside an acceptable range, e.g., if the pressuredifferential is excessive. The circuit 56 may further be programmed topermit the actuator 36 to displace the sleeve 18 to the equalizingposition, but not to the open position, if the pressure differentialacross the sleeve is excessive.

[0043] Thus, it will be readily appreciated that the method 10 providesfor convenient operation of the tool 12 in conjunction with the valve16, with reduced possibility of human error involved therewith. Anoperator may convey the tool 12 into the string 14, the tool and thevalve 16 may communicate via the devices 38, 42 and/or 40, 44 toindicate the identity of the valve and/or to select the valve from amongmultiple items of equipment installed in the string, and suchcommunication may be used to indicate that the tool is operativelypositioned relative to the valve, to control engagement of the tool withthe valve, to indicate useful status information regarding the valve,such as the position of the sleeve 18, pressure applied to the valve,pressure differential across the sleeve, etc., and to control operationof the tool. Due to the advances in the art provided by the method 10,when the tool 12 is utilized additionally to transmit information to aremote location, the operator is able to positively determine whetherthe valve 16 is the appropriate item of equipment intended to be engagedby the tool, whether the tool is operatively positioned relative to thevalve, whether the tool has operatively engaged the valve, the positionof the sleeve 18 both before and after it is displaced, if at all, bythe tool, and the pressures and/or differential pressures, temperatures,etc. of concern.

[0044] Referring additionally now to FIG. 2, alternate communicationdevices 58, 60 are representatively and schematically illustrated whichmay be used for the devices 38, 42 described above. As depicted in FIG.2, the devices 58, 60 are shown installed in the actuator 36 and housing20 of the method 10, but it is to be clearly understood that the devices58, 60 may be used in other apparatus, other methods, and insubstitution for other communication devices described herein, withoutdeparting from the principles of the present invention.

[0045] The devices 58, 60 communicate by inductive couplingtherebetween. Power may also be supplied from the device 58 to thedevice 60 by such inductive coupling.

[0046] The device 38 includes an annular-shaped coil 62, which isconnected to an electronic circuit 64. The circuit 64 causes electricalcurrent to be flowed through the coil 62, and manipulates that currentto cause the device 58 to transmit a signal to the device 60. Note thatsuch signaling is via a magnetic field, and manipulations of themagnetic field, propagated by the coil 62 in response to the currentflowed therethrough. The device 58 may also respond to a magnetic field,for example, propagated by the device 60, in which case the magneticfield would cause a current to flow through the coil 62 and be receivedby the circuit 64. Thus, the device 58 may serve as a transmitter orreceiver.

[0047] The device 60 also includes a coil 66 and a circuit 68 connectedto the coil. The device 60 may operate in a manner similar to thatdescribed above for the device 58, or it may operate differently. Forexample, the device 60 may only transmit signals, without beingconfigured for receiving signals.

[0048] Referring additionally now to FIG. 3, further alternatecommunication devices 70, 72 are representatively and schematicallyillustrated which may be used for the devices 38, 42 described above. Asdepicted in FIG. 3, the devices 70, 72 are shown installed in theactuator 36 and housing 20 of the method 10, but it is to be clearlyunderstood that the devices 70, 72 may be used in other apparatus, othermethods, and in substitution for other communication devices describedherein, without departing from the principles of the present invention.

[0049] The devices 70, 72 communicate by transmission of electromagneticwaves therebetween, preferably using radio frequency (RF) transmission.Power may also be supplied from the device 70 to the device 72 by suchelectromagnetic wave transmission.

[0050] The device 70 includes an antenna 74, which is connected to anelectronic circuit 76. The circuit 76 causes electrical current to beflowed through the antenna 74, and manipulates that current to cause thedevice 70 to transmit a signal to the device 72. The device 70 may alsorespond to electromagnetic wave transmission from the device 72, inwhich case the device 70 may also serve as a receiver.

[0051] The device 72 also includes an antenna 78 and a circuit 80connected to the antenna. The device 72 may operate in a manner similarto that described above for the device 70, or it may operatedifferently. For example, the device 72 may only transmit signals,without being configured for receiving signals.

[0052] Referring additionally now to FIG. 4., still further alternatecommunication devices 82, 84 are representatively and schematicallyillustrated which may be used for the devices 38, 42 described above. Asdepicted in FIG. 4, the devices 82, 84 are shown installed in theactuator 36 and housing 20 of the method 10, but it is to be clearlyunderstood that the devices 82, 84 may be used in other apparatus, othermethods, and in substitution for other communication devices describedherein, without departing from the principles of the present invention.

[0053] The devices 82, 84 communicate by transmission of pressure pulsestherebetween, preferably using acoustic wave transmission. Power mayalso be supplied from the device 82 to the device 84 by such pressurepulses.

[0054] The device 82 includes at least one piezoelectric crystal 86,which is connected to an electronic circuit 88. The circuit 88 causeselectrical current to be flowed through the crystal 86, and manipulatesthat current to cause the device 82 to transmit a signal to the device84. The device 82 may also respond to pressure pulses transmitted fromthe device 84, in which case the device 82 may also serve as a receiver.

[0055] The device 84 also includes a piezoelectric crystal 90 and acircuit 92 connected to the crystal. The device 84 may operate in amanner similar to that described above for the device 82, or it mayoperate differently. For example, the device 34 may only transmitsignals, without being configured for receiving signals.

[0056] Of course, it is well known that a piezoelectric crystal distortswhen an electric current is applied thereto, and that distortion of apiezoelectric crystal may be used to generate an electric currenttherefrom. Thus, when the circuit 88 applies a current, or manipulates acurrent applied to, the crystal 86, the crystal distorts and causes apressure pulse or pulses in fluid disposed between the actuator 36 andthe housing 20. This pressure pulse or pulses, in turn, causes thecrystal 90 to distort and thereby causes a current, or a manipulation ofa current, to be flowed to the circuit 92. In a similar manner, thedevice 84 may transmit a signal to the device 82. Multiple ones ofeither or both of the crystals 86, 90 may be used, if desired, toincrease the amplitude of the pressure pulses generated thereby, or toincrease the amplitude of the signal generated when the pressure pulsesare received.

[0057] Thus have been described several alternate means by which devicesmay communicate between an item of equipment interconnected in a tubularstring and a toot conveyed into the string. It is to be clearlyunderstood however, that any type of communication device may be usedfor the communication devices described herein, and that the principlesof the present invention are not to be considered as limited to thespecifically described communication devices. Many other communicationdevices, and other types of communication devices, may be used inmethods and apparatus incorporating principles of the present invention.For example, the crystal 90 could be a radioactivity producing deviceand the crystal 86 could be a radioactivity sensing device, the crystal90 could be a magnet and the crystal 86 could be a hall effect device ora reed switch which closes in the presence of a magnetic field, etc.Furthermore, each of the communication devices described herein may havea power source incorporated therein, for example, a battery may beincluded in the each of the circuits 64, 68, 76, 80, 88, 92 describedabove.

[0058] Referring additionally now to FIGS. 5A&B, a method 100 whichembodies principles of the present invention is representatively andschematically illustrated. The method 100 is similar in many respects tothe method 10 described above, in that a tool 102 is engaged with anitem of equipment 104 installed in a tubular string and communication isestablished between a communication device 106 of the tool and acommunication device 108 of the item of equipment. As depicted in FIGS.5A&B, the item of equipment 104 is a plug system and the tool 102 is aretrieving tool, but it is to be understood that principles of thepresent invention may be incorporated in other tools and items ofequipment.

[0059] The plug system 104 includes a closure member, pressureequalizing member or prong 110, which is sealingly received within aplug assembly 112. The plug assembly 112, in turn, is sealingly engagedwithin a nipple 114. The nipple 114 is of the type well known to thoseskilled in the art and which may be interconnected in a tubular string,but is shown apart from the tubular string for illustrative clarity.

[0060] The plug assembly 112 includes a lock mandrel 134, whichreleasably secures the plug assembly relative to the nipple 114, and aplug 136, which sealingly engages the nipple to block fluid flowtherethrough. The plug system 104 may be considered to include thenipple 114, although the plug assembly 112 and prong 110 may be used toblock fluid flow through other nipples or other tubular members and,thus, the plug assembly and prong may also be considered to comprise aplugging device apart from the nipple.

[0061] The device 108 may be supplied with power by a battery or otherpower source 109. The power source 109 may be included in the plugsystem 104, or it may be remote therefrom. It is to be clearlyunderstood that any means of supplying power to the device 108 may beutilized, without departing from the principles of the presentinvention. The power source 109 may also supply power to sensors, etc.associated with the device 108.

[0062] When the prong 110 is sealingly received within the plug assembly112 as shown in FIG. 5B, fluid flow axially through the nipple 114 (andthrough the plug 136) is prevented. When the prong 110 is displacedupwardly relative to the plug assembly 112 and nipple 114, fluid flow ispermitted through one or more relatively small openings 116 formedthrough a sidewall of the plug 136. Such fluid flow through the opening116 may be used to equalize pressure across the plug assembly 112 beforeretrieving the plug assembly from the nipple. Note that, when the plugassembly 112 is removed from the nipple 114, relatively unrestrictedfluid flow is permitted axially through the nipple.

[0063] A pressure sensor 118 is included in the prong 110 and is exposedto pressure in the nipple 114 below the plug assembly 112. Anotherpressure sensor 120 is included in the tool 102 and is exposed topressure in the nipple 114 above the plug assembly 112. The pressuresensor 118 is connected to the device 108, which permits communicationof pressure data from the sensor to the device 106. Pressure data fromthe sensor 118 (via the devices 106, 108) and pressure data from thesensor 120 may be input to an electronic circuit 122 of the tool 102and/or transmitted to a remote location. Such pressure data may be usedto determine pressures applied to the prong 110, plug assembly 112and/or nipple 114, and may be used to determine the pressuredifferential across the plug assembly. The circuit 122 (or anothercircuit, e.g., at a remote location) may be programmed to preventoperation of the tool 102 to displace the prong 110 if the pressuredifferential is excessive, or to permit only limited displacement of theprong if the pressure differential is excessive. Another pressure sensor132 may optionally be included in the prong 110 for measurement ofpressure in the nipple 114 above the plug assembly 112.

[0064] The tool 102 includes one or more engagement members 124configured for operatively engaging an external profile 126 formed onthe prong 110. Such engagement permits the tool 102 to apply an upwardlydirected force to the prong 110. Another portion (not shown) of the tool102 may be engaged with another profile for releasably securing the toolrelative to the nipple 114 or plug assembly 112, similar to the mannerin which the tool 12 is releasably secured relative to the valve 16using the keys 28 and profile 30 described above. For example, the tool102 could have a portion which engages an internal profile 128 formed onthe mandrel 134. In that case, the tool 102 would be releasably securedto the mandrel 134, and could be used to retrieve the mandrel byapplying an upwardly directed force to the profile 128 if desired.

[0065] The engagement member 124 is displaced into engagement with theprofile 126 by an actuator 130, which is connected to the circuit 122(or to another circuit, e.g., at a remote location). The circuit 122 maybe programmed or configured to permit the actuator 130 to displace theengagement member 124 into engagement with the profile 126 only whencommunication between the devices 106, 108 indicates that the tool 102is operatively positioned relative to the prong 110, nipple 114 or plugassembly 112. The representatively illustrated devices 106, 108communicate by direct electrical contact, so establishment ofcommunication therebetween may be the indication that the tool 102 isoperatively positioned.

[0066] Alternatively, the circuit 122 may be programmed to permitengagement between the engagement member 124 and the profile 126 onlywhen the pressure differential across the prong 110 and plug assembly112 is within an acceptable range, or at least not excessive, although,since displacement of the prong is utilized to cause reduction of thepressure differential as described above, this alternative is notpreferred. As another alternative, the tool 102 may be prevented fromengaging the profile 128, or may be prevented from displacing the plugassembly 112 relative to the nipple 114, if the pressure differentialacross the prong 110 and plug assembly is excessive.

[0067] The method 100 demonstrates that principles of the presentinvention may be incorporated into a variety of different apparatus andmethods. Thus, the principles of the present invention are not to beconsidered limited to the specific apparatus and method embodimentsdescribed herein.

[0068] Referring additionally now to FIG. 6, another method 140embodying principles of the present invention is representatively andschematically illustrated. In the method 140, multiple items ofequipment 142, 144 are placed in communication with a service tool 146conveyed into a tubular string 148. The item of equipment 142 is aportion of the tubular string 148, and the item of equipment 144 is apacker.

[0069] The tool 146 includes a communication device 150, and anothercommunication device 152 is included in the string portion 142. Asdepicted in FIG. 6, the devices 150, 152 communicate via inductivecoupling, in a manner similar to communication between the devices 58,60 described above.

[0070] The device 152 is connected to various sensors of the stringportion 142 and packer 144. For example, a sensor 154 may be positionedexternally relative to the string portion 142, and a sensor 156 may bepositioned internally relative to the packer 144. Additionally, othersensors 158, 160 may be positioned in the string 148 and connected tothe device 152.

[0071] The sensor 154 may be a strain gauge, in which case indicationsof strain in the string 148 may be communicated from the device 152 tothe device 150 for storage in a memory device of the tool 146 for laterretrieval, e.g., at the earth's surface, or the tool 146 may transmitthe indications to a remote location. Such a strain gauge sensor 154 maybe utilized, for example, to identify problematic displacement of thestring portion 142, which could prevent insertion of a tool stringtherethrough, or to monitor fatigue in the tubing string 148.

[0072] The sensor 154 may alternatively, or additionally, be a pressuresensor, temperature sensor, or any other type of sensor. For example,the sensor 154 may be utilized to indicate pressure applied to thestring portion 142 or a pressure differential across the string portion.To indicate a pressure differential across the string portion 142,another of the sensors 154 may be positioned internal to the stringportion.

[0073] The sensors 158, 160 may be pressure sensors, in which caseindications of pressure above and below the packer 144 may becommunicated via the devices 150, 152 to the tool 146 and stored thereinor transmitted to a remote location. The sensors 158, 160 may beincluded in the packer 144, and may indicate a pressure differentialacross a seal member or element 168 of the packer.

[0074] Note that the device 152 is remotely located relative to thesensors 156, 158, 160 and packer 144. Thus, it will be readilyappreciated that a communication device is not necessarily included in aparticular item of equipment or in the same item of equipment as asource of data communicated by the device, in keeping with theprinciples of the present invention.

[0075] Referring additionally now to FIG. 7, the packer 144 is shown inan enlarged quarter-sectional view. In this view, the sensor 156 isdepicted as actually including multiple individual sensors 162, 164,166. The packer 144 includes the seal member or element 168, which isradially outwardly extended into sealing engagement with a wellbore 170of the well.

[0076]FIG. 7 also depicts a seal assembly 180 sealingly received in thepacker 144. Confirmation that the seal assembly 180 is properlypositioned relative to the packer 144 is provided by a position sensor178 of the packer. The position sensor 178 is connected to the device152, so that an indication that the seal assembly 180 is properlypositioned relative to the packer 144 may be transmitted to an operator.The position sensor 178 may be a proximity sensor, a hall effect device,fiber optic device, etc., or any other sensor capable of detecting theposition of the seal assembly 180 relative to the packer 144.

[0077] The sensor 162 may be a compression or pressure sensor configuredfor measuring compression or pressure in the seal member 168. The sensor166 may be a temperature sensor for measuring the temperature of theseal member 168. Alternatively, one or both of the sensors 162, 166 maybe a resistivity sensor, strain sensor or hardness sensor. Thus, it willbe readily appreciated that any type of sensor may be included in thepacker 144, without departing from the principles of the presentinvention.

[0078] The sensor 164 is a special type of sensor incorporatingprinciples of the present invention. The sensor 164 includes a portion172 configured for inducing vibration in the seal member 168, and aportion 174 configured for measuring a resonant frequency of the sealmember. In operation of the sensor 164, the vibrating portion 172 isactivated to cause a projection 176 extending into the seal member 168to vibrate. For example, the vibrating portion 172 may include apiezoelectric crystal to which is applied an alternating current. Thecrystal vibrates in response to the current, and thereby causes theprojection 176, which is attached to the crystal, to vibrate also. Thisvibration of the projection 176 in turn causes the seal member 168 tovibrate. Of course, the crystal could be directly contacting the sealmember 168, in which case vibration of the crystal could directly causevibration of the seal member 168, without use of the projection 176.Other methods of inducing vibration in the seal member may be utilized,without departing from the principles of the present invention.

[0079] When vibration has been induced in the seal member 168, it willbe readily appreciated that the seal member will vibrate at its naturalor resonant frequency. The frequency measuring portion 174 detects theresonant frequency vibration of the seal member 168, and data indicatingthis resonant frequency is communicated by the devices 150, 152 to thetool 146 for storage therein and/or transmission to a remote location.Note that it is not necessary for the vibrating and frequency measuringportions 172, 174 to be separate portions of the sensor 164 since, forexample, a piezoelectric crystal may be used both to induce vibration inthe seal element 168 and to detect vibration of the seal element.

[0080] The resonant frequency of the seal member 168 may be used, forexample, to determine the hardness of the seal member and/or theprojected useful life of the seal member. The strain in the tubularstring 148 as detected by the sensor 154 may be used, for example, todetermine a radius of curvature of the string and/or the projecteduseful life of the string. Thus, a wide variety of useful informationregarding items of equipment installed in the well may be acquired bythe tool 146 in a convenient manner.

[0081] The device 152 may be supplied with power by a battery or otherpower source 153. The power source 153 may be included in the packer144, or it may be remote therefrom. It is to be clearly understood thatany means of supplying power to the device 152 may be utilized, withoutdeparting from the principles of the present invention. The power source153 may also supply power to the sensors 154, 156, 158, 160, 178associated with the device 152. Alternatively, one or more of thesensors 154, 156, 158, 160, 178 may have a power source, such as abattery, combined therewith or integral thereto, so that a remote powersource is not needed to operate the sensor. Note that any of the othersensors 50, 51, 52, 54, 118, 120, 132 described above may also include apower source. In each of the methods 10, 100, 140 described above, apower source included in any sensor used in the method may supply powerto operate its associated communication device.

[0082] A memory device 182, such as a random access memory device, isshown in FIG. 7 included in the packer 144 and interconnected to thesensors 162, 164, 166. The memory device 182 is utilized to store datagenerated by the sensors 162, 164, 166, and then transmit the storeddata to the tool 146 via the devices 150, 152. In this manner, thememory device may store, for example, indications of the hardness of, orcompression in, the seal element 168 over time, and these readings maythen be retrieved by the tool 146 and stored therein, or be transmitteddirectly to a facility at the earth's surface, for evaluation.

[0083] Note that, although the memory device 182 is shown as beingincluded in the packer 144, it may actually be remotely positionedrelative to the packer. For example, the memory device 182 could bepackaged with the communication device 152. In addition, the memorydevice 182 may be connected to other sensors, such as the sensor 154.Power to operate the memory device 182 may be supplied by the powersource 153, or another power source.

[0084] Referring additionally now to FIG. 8, another method 190embodying principles of the present invention is schematically andrepresentatively illustrated. In the method 190, an item of equipment192 is interconnected in a tubular string 194. The item of equipment 192includes a nipple 200 or other tubular housing and a particle sensor 196of the type capable of detecting particles, such as sand grains, passingthrough the nipple.

[0085] A memory device 198, such as a random access memory device, isconnected to the sensor 196 and stores data generated by the sensor. Thesensor 196 is also connected to a communication device 202. Thecommunication device 202 is configured for communication with anothercommunication device 204 included in a service tool 206. Thecommunication devices 202, 204 may be similar to any of thecommunication devices described above, other they may be other types ofcommunication devices.

[0086] When the tool 206 is received in the nipple 200 and appropriatelypositioned relative thereto, the devices 202, 204 communicate, therebypermitting download of the data stored in the memory device 198. Thisdata may be stored in another memory device of the tool 206 for laterretrieval, or it may be communicated directly to a remote location.

[0087] Power to operate the sensor 196, the memory device 198 and/or thecommunication device 202 may be supplied by a power source 208, such asa battery, included with the sensor. Alternatively, the communicationdevice 202 could be supplied with power from the communication device204, as described above. As another alternative, the power source maynot be included with the sensor, but may be remotely positioned relativethereto.

[0088] Note that it is not necessary for the data generated by thesensor 196 to be stored in the memory device 198, since data may betransmitted directly from the sensor to the tool 206 via the devices202, 204 in real time.

[0089] It will now be fully appreciated that the method 190 permitsevaluation of particle flow through the nipple 200 over time. The datafor such evaluation may be conveniently obtained by conveying the tool206 into the nipple 200 and establishing communication between thedevices 202, 204. This evaluation may assist in predicting futureparticle production, assessing the effectiveness of a sand controlprogram, etc.

[0090] It is to be clearly understood that, although the method 190 hasbeen described herein as being used to evaluate particle flow axiallythrough the tubular member 200, principles of the present invention mayalso be incorporated in methods wherein other types of particle flowsare experienced. For example, the sensor 51 of the method 10 may be aparticle sensor, in which case particle flow through a sidewall of thehousing 20 may be evaluated.

[0091] The method 190 may also utilize functions performed by thecommunication devices as described above. For example, the communicationdevice 202 may communicate to the communication device 204 an indicationthat the tool 206 is operatively positioned, or within a predetermineddistance of an operative position, relative to the item of equipment192. The communication device 204 may activate the communication device202 from a dormant state to an active state, thereby permittingcommunication between the devices.

[0092] Of course, a person skilled in the art, upon a carefulconsideration of the above description of various embodiments of thepresent invention would readily appreciate that many modifications,additions, substitutions, deletions and other changes may be made to theapparatus and methods described herein, and these changes arecontemplated by the principles of the present invention. For example,although certain types of sensors have been described above as beinginterconnected to communication devices, any type of sensor may be usedin any of the above described apparatus and methods, and thecommunication devices described above may be used in conjunction withany type of sensor. As another example, items of equipment have beendescribed above as being interconnected in tubing strings, butprinciples of the present invention may be incorporated in methods andapparatus wherein items of equipment are interconnected or installed inother types of tubular strings, such as casing or coiled tubing.Accordingly, the foregoing detailed description is to be clearlyunderstood as being given by way of illustration and example only, thespirit and scope of the present invention being limited solely by theappended claims.

What is claimed is:
 1. A system for facilitating downhole communicationbetween an item of equipment installed in a tubular string in asubterranean well and a tool conveyed into the tubular string, thesystem comprising: a first communication device associated with the itemof equipment; and a second communication device included in the tool,communication between the first and second devices being establishedwhen the second device is brought into sufficiently close proximity tothe first device.
 2. The system according to claim 1 , wherein thesecond device supplies power to the first device, thereby permitting thefirst device to communicate with the second device.
 3. The systemaccording to claim 2 , wherein the power is supplied by electromagneticwaves emanating from the second device.
 4. The system according to claim3 , wherein the electromagnetic waves are radio frequency waves.
 5. Thesystem according to claim 2 , wherein the power is supplied by pressurepulses emanating from the second device.
 6. The system according toclaim 5 , wherein the pressure pulses are acoustic waves.
 7. The systemaccording to claim 2 , wherein the power is supplied by directelectrical contact between the first and second devices.
 8. The systemaccording to claim 2 , wherein the power is supplied by inductivecoupling between the first and second devices.
 9. The system accordingto claim 1 , wherein the second device activates the first device from adormant state to an active state, thereby permitting communicationbetween the first and second devices.
 10. The system according to claim9 , wherein the communication between the first and second devices isvia electromagnetic waves.
 11. The system according to claim 10 ,wherein the electromagnetic waves are radio frequency waves.
 12. Thesystem according to claim 9 , wherein the communication between thefirst and second devices is via pressure pulses.
 13. The systemaccording to claim 12 , wherein the pressure pulses are acoustic waves.14. The system according to claim 9 , wherein the communication betweenthe first and second devices is via direct electrical contact betweenthe first and second devices.
 15. The system according to claim 9 ,wherein the communication between the first and second devices is viainductive coupling between the first and second devices.
 16. The systemaccording to claim 1 , wherein the communication between the first andsecond devices indicates when the tool is within a predetermineddistance of an operative position of the tool relative to the item ofequipment.
 17. The system according to claim 16 , wherein the firstdevice communicates to the second device that the tool is operativelypositioned relative to the item of equipment.
 18. The system accordingto claim 16 , wherein the item of equipment has a profile, the tool hasan engagement member configured for engagement with the profile tosecure the tool relative to the item of equipment, and wherein thecommunication between the first and second devices indicates when theengagement member is aligned with the profile.
 19. The system accordingto claim 18 , wherein the tool is permitted to displace the engagementmember into engagement with the profile only when the communicationbetween the first and second devices indicates that the engagementmember is aligned with the profile.
 20. The system according to claim 1, wherein the first device communicates a status of the item ofequipment to the second device.
 21. The system according to claim 20 ,wherein the item of equipment is a valve, and wherein the status is aposition of the valve.
 22. The system according to claim 20 , whereinthe item of equipment is a packer, and wherein the status of a sealmember of the packer is communicated to the second device.
 23. Thesystem according to claim 22 , wherein the status is a hardness of theseal member.
 24. The system according to claim 22 , wherein the statusis compressive stress in the seal member.
 25. The system according toclaim 20 , wherein the item of equipment is a portion of the tubularstring, and wherein the status is a strain in the portion of the tubularstring.
 26. The system according to claim 1 , wherein communicationbetween the first and second devices at least partially controlsoperation of the tool.
 27. The system according to claim 26 , wherein anengagement member of the tool is permitted to engage a profile of theitem of equipment when the first and second devices are in sufficientlyclose proximity to each other.
 28. The system according to claim 27 ,wherein the profile is internally formed.
 29. The system according toclaim 27 , wherein the profile is externally formed.
 30. The systemaccording to claim 26 , wherein the toot is permitted to displace aclosure member of the item of equipment when the communication betweenthe first and second devices indicates that a pressure differentialacross the closure member is within a predetermined range.
 31. Thesystem according to claim 30 , wherein the tool is permitted to displacethe closure member to an equalizing position configured for reducing thepressure differential, but the tool is permitted to displace the closuremember to an open position only when the communication between the firstand second devices indicates that the pressure differential is withinthe predetermined range.
 32. The system according to claim 30 , whereinthe closure member is a pressure equalizing member, wherein the tool ispermitted to displace the pressure equalizing member to an equalizingposition configured for reducing the pressure differential, but the toolis permitted to remove the pressure equalizing member from the item ofequipment only when the communication between the first and seconddevices indicates that the pressure differential is within thepredetermined range.
 33. The system according to claim 26 , wherein theitem of equipment is one of a plurality of structures interconnected inthe tubular string, and wherein the item of equipment is selected fromthe plurality of structures for operation of the tool therewith inresponse to the communication between the first and second devices. 34.The system according to claim 33 , wherein the tool is programmable forselection of multiple ones of the plurality of structures for operationof the tool therein in response to communication between the seconddevice and a device of each of the selected structures.
 35. The systemaccording to claim 1 , wherein the first device is remotely positionedrelative to the remainder of the item of equipment.
 36. The systemaccording to claim 1 , wherein the first device includes an electroniccircuit, and wherein the second device is responsive to a signalproduced by the electronic circuit.
 37. The system according to claim 1, wherein the first device includes a magnet, and wherein the seconddevice is responsive to a magnetic field produced by the magnet.
 38. Thesystem according to claim 1 , wherein the first device includes aradioactive device, and wherein the second device is responsive toradioactivity produced by the radioactive device.
 39. The systemaccording to claim 1 , wherein the first device includes a reed switch,and wherein the second device is responsive to actuation of the reedswitch.
 40. The system according to claim 1 , wherein the first deviceincludes a hall effect device, and wherein the second device causes thehall effect device to generate an electrical current.
 41. The systemaccording to claim 1 , wherein the first device identifies the item ofequipment to the tool.
 42. The system according to claim 1 , wherein thefirst device responds to a magnet to activate the first device from adormant state to an active state.
 43. The system according to claim 1 ,wherein the first device responds to radioactivity to activate the firstdevice from a dormant state to an active state.
 44. The system accordingto claim 1 , wherein the first device responds to a signal transmittedfrom the second device to activate the first device from a dormant stateto an active state.
 45. The system according to claim 1 , wherein thefirst device is connected to a sensor of the item of equipment andcommunication between the first and second devices transmits data fromthe sensor.
 46. The system according to claim 45 , wherein the sensorincludes a power source.
 47. The system according to claim 46 , whereinpower to operate the first device is provided by the sensor powersource.
 48. A downhole valve system, comprising: a valve including aclosure member selectively positionable in open and closed positions,and a first communication device; and a tool positionable relative tothe first device and operable to cause displacement of the closuremember between the open and closed positions, the tool including asecond communication device, with communication being establishedbetween the first and second devices.
 49. The valve system according toclaim 48 , wherein the tool is permitted to displace the closure memberonly when predetermined acceptable data is transmitted from at least onesensor via the first and second devices.
 50. The valve system accordingto claim 48 , wherein the first device communicates data indicative ofpressure applied to the closure member.
 51. The valve system accordingto claim 50 , wherein the first device is connected to a pressure sensorof the valve.
 52. The valve system according to claim 50 , wherein thefirst device communicates data indicative of a pressure differentialacross the closure member.
 53. The valve system according to claim 50 ,wherein data is communicated from the first to the second device, andwherein the tool transmits the data to a remote location.
 54. The valvesystem according to claim 48 , wherein the first device communicatesdata indicative of the position of the closure member to the seconddevice.
 55. The valve system according to claim 54 , wherein the firstdevice is connected to a position sensor.
 56. The valve system accordingto claim 54 , wherein the first device is connected to a pressuresensor.
 57. The valve system according to claim 54 , wherein the tooltransmits the data to a remote location.
 58. The valve system accordingto claim 48 , wherein the tool is permitted to displace the closuremember to the open position only when a differential pressure across theclosure member is within a predetermined range.
 59. The valve systemaccording to claim 48 , wherein the tool is permitted to displace theclosure member to an equalizing position configured for reducing apressure differential across the closure member, but the tool ispermitted to displace the closure member to the open position only whenthe pressure differential is within a predetermined range.
 60. The valvesystem according to claim 48 , wherein the tool includes a firstpressure sensor sensing pressure on a first side of the closure member,and the valve includes a second pressure sensor sensing pressure on asecond side of the closure member.
 61. The valve system according toclaim 48 , wherein the valve includes a first pressure sensor sensingpressure on a first side of the closure member, and a second pressuresensor sensing pressure on a second side of the closure member.
 62. Thevalve system according to claim 48 , wherein the tool includes anengagement member which is permitted to engage the valve only when thesecond device is in sufficiently close proximity to the first device.63. The valve system according to claim 48 , wherein the valve is one ofa plurality of structures interconnected in the tubular string, andwherein the valve is selected from the plurality of structures foroperation of the tool therewith in response to the communication betweenthe first and second devices.
 64. The valve system according to claim 63, wherein each of the structures has a communication device associatedtherewith, and wherein the tool is programmed to activate only the firstdevice from a dormant state to an active state.
 65. The valve systemaccording to claim 63 , wherein each of the structures has acommunication device associated therewith, and wherein the first deviceis activated from a dormant state to an active state only in response tocommunication from the second device.
 66. The valve system according toclaim 48 , wherein power for operation of the first device is suppliedby the tool.
 67. The valve system according to claim 48 , wherein thefirst device is connected to a sensor including a power source.
 68. Thevalve system according to claim 67 , wherein power to operate the firstdevice is supplied by the sensor power source.
 69. The valve systemaccording to claim 48 , wherein power for operation of the first deviceis supplied by a power source of the valve.
 70. The valve systemaccording to claim 69 , wherein the power source is remotely positionedrelative to the valve.
 71. The valve system according to claim 48 ,wherein the first device is remotely positioned relative to the valve.72. The valve system according to claim 48 , wherein the valve furtherincludes an opening formed through a sidewall of the valve, fluidflowing through the opening when the closure member is in the openposition, and a sensor interconnected to the first device and sensing aproperty of a fluid flowing through the opening.
 73. The valve systemaccording to claim 72 , wherein the sensor is a resistivity sensor. 74.The valve system according to claim 72 , wherein the sensor is acapacitance sensor.
 75. The valve system according to claim 72 , whereinthe sensor is an inductance sensor.
 76. The valve system according toclaim 72 , wherein the sensor is a particle sensor.
 77. A downhole plugsystem, comprising: a plug assembly; a first communication device; aclosure member selectively positionable in engaged and releasedpositions relative to the plug assembly, the closure member blockingflow through the plug assembly in the engaged position, and flow throughthe plug assembly being permitted in the released position; and a toolpositionable relative to the first device and operable to causedisplacement of the closure member between the engaged and releasedpositions, the tool including a second communication device, andcommunication being established between the first and second devices.78. The plug system according to claim 77 , wherein the first devicecommunicates data indicative of pressure applied to the closure member.79. The plug system according to claim 78 , wherein the first device isconnected to a pressure sensor of the closure member.
 80. The plugsystem according to claim 78 , wherein the first device communicatesdata indicative of a pressure differential across the closure member.81. The plug system according to claim 78 , wherein data is communicatedfrom the first to the second device, and wherein the tool transmits thedata to a remote location.
 82. The plug system according to claim 77 ,wherein the tool is permitted to displace the closure member only whenpredetermined acceptable data is transmitted from at least one sensorvia the first and second devices.
 83. The plug system according to claim77 , wherein the tool is permitted to displace the closure member to thereleased position only when a differential pressure across the closuremember is within a predetermined range.
 84. The plug system according toclaim 77 , wherein the released position is an equalizing positionconfigured for reducing a pressure differential across the closuremember.
 85. The plug system according to claim 77 , wherein the toolincludes a first pressure sensor sensing pressure on a first side of theclosure member, and the closure member includes a second pressure sensorsensing pressure on a second side of the closure member.
 86. The plugsystem according to claim 77 , further comprising a first pressuresensor sensing pressure on a first side of the closure member, and asecond pressure sensor sensing pressure on a second side of the closuremember.
 87. The plug system according to claim 77 , wherein the toolincludes an engagement member which is permitted to engage the closuremember only when the second device is in sufficiently close proximity tothe first device.
 88. The plug system according to claim 77 , whereinthe plug assembly is one of a plurality of structures interconnected inthe tubular string, and wherein the plug assembly is selected from theplurality of structures for operation of the tool therewith in responseto the communication between the first and second devices.
 89. The plugsystem according to claim 88 , wherein each of the structures has acommunication device associated therewith, and wherein the tool isprogrammed to activate only the first device from a dormant state to anactive state.
 90. The plug system according to claim 88 , wherein eachof the structures has a communication device associated therewith, andwherein the first device is activated from a dormant state to an activestate only in response to communication from the second device.
 91. Theplug system according to claim 77 , wherein power for operation of thefirst device is supplied by the tool.
 92. The plug system according toclaim 77 , wherein power for operation of the first device is suppliedby a power source of the closure member.
 93. The plug system accordingto claim 77 , wherein the first device is connected to a sensorincluding a power source.
 94. The plug system according to claim 93 ,wherein power for operation of the first device is supplied by thesensor power source.
 95. A downhole packer system, comprising: a packerincluding a first communication device and an outwardly extendable sealmember; and a tool positionable relative to the first device andincluding a second communication device, communication being establishedbetween the first and second devices.
 96. The packer system according toclaim 95 , wherein the first device communicates data indicative ofpressure applied to the seal member.
 97. The packer system according toclaim 96 , wherein the first device is connected to a pressure sensor ofthe packer.
 98. The packer system according to claim 96 , wherein thefirst device communicates data indicative of a pressure differentialacross the seal member.
 99. The packer system according to claim 96 ,wherein data is communicated from the first to the second device, andwherein the tool transmits the data to a remote location.
 100. Thepacker system according to claim 95 , wherein the first device isremotely positioned relative to the remainder of the packer.
 101. Thepacker system according to claim 95 , wherein the packer includes afirst pressure sensor sensing pressure on a first side of the sealmember, and a second pressure sensor sensing pressure on a second sideof the seal member.
 102. The packer system according to claim 95 ,wherein the packer is one of a plurality of structures interconnected inthe tubular string, and wherein the packer is selected from theplurality of structures for operation of the tool therewith in responseto the communication between the first and second devices.
 103. Thepacker system according to claim 102 , wherein each of the structureshas a communication device associated therewith, and wherein the tool isprogrammed to activate only the first device from a dormant state to anactive state.
 104. The packer system according to claim 102 , whereineach of the structures has a communication device associated therewith,and wherein the first device is activated from a dormant state to anactive state only in response to communication from the second device.105. The packer system according to claim 95 , wherein power foroperation of the first device is supplied by the tool.
 106. The packersystem according to claim 95 , wherein power for operation of the firstdevice is supplied by a power source of the packer.
 107. The packersystem according to claim 95 , wherein the first device is connected toa sensor including a power source.
 108. The packer system according toclaim 107 , wherein power to operate the first device is supplied by thesensor power source.
 109. The packer system according to claim 95 ,wherein the first device is connected to a seal member sensor.
 110. Thepacker system according to claim 109 , wherein the seal member sensor isa temperature sensor.
 111. The packer system according to claim 109 ,wherein the seal member sensor is a compression sensor.
 112. The packersystem according to claim 109 , wherein the seal member sensor is aresistivity sensor.
 113. The packer system according to claim 109 ,wherein the seal member sensor is a strain sensor.
 114. The packersystem according to claim 109 , wherein the seal member sensor is ahardness sensor.
 115. The packer system according to claim 109 , whereinthe seal member sensor is a resonant frequency sensor.
 116. The packersystem according to claim 115 , wherein the seal member sensor inducesvibration in the seal member.
 117. The packer system according to claim95 , wherein the packer includes a position sensor.
 118. The packersystem according to claim 117 , wherein the position sensor indicates aposition of a seal assembly relative to the packer.
 119. The packersystem according to claim 95 , wherein the first device communicatesdata indicative of a position of a seal assembly relative to the packer.120. A downhole tubular string monitoring system, comprising: a tubularstring including a first sensor and a first communication devicecommunicating data acquired by the first sensor; and a tool positionablerelative to the first device and including a second communication devicecommunicating with the first device.
 121. The monitoring systemaccording to claim 120 , wherein the communicated data is indicative ofpressure applied to the first sensor.
 122. The monitoring systemaccording to claim 120 , wherein the first device communicates dataindicative of a pressure differential across the tubular string. 123.The monitoring system according to claim 120 , wherein the tooltransmits the data to a remote location.
 124. The monitoring systemaccording to claim 120 , wherein the first device is remotely positionedrelative to the first sensor.
 125. The monitoring system according toclaim 120 , wherein the tool includes a second sensor sensing pressureon the interior of the tubular string, and wherein the first sensorsenses pressure on the exterior of the tubular string.
 126. Themonitoring system according to claim 120 , wherein the first device isone of a plurality of communication devices interconnected in thetubular string, and wherein the first device is selected from theplurality of structures for operation of the tool therewith in responseto the communication between the first and second devices.
 127. Themonitoring system according to claim 120 , wherein the first device isactivated from a dormant state to an active state only in response tocommunication from the second device.
 128. The monitoring systemaccording to claim 120 , wherein power for operation of the first deviceis supplied by the tool.
 129. The monitoring system according to claim120 , wherein power for operation of the first device is supplied by apower source interconnected in the tubular string.
 130. The monitoringsystem according to claim 120 , wherein the first device is connected toa sensor including a power source.
 131. The monitoring system accordingto claim 130 , wherein power to operate the first device is supplied bythe sensor power source.
 132. The monitoring system according to claim120 , wherein the first sensor is a strain sensor.
 133. The monitoringsystem according to claim 120 , wherein the first sensor is atemperature sensor.
 134. The monitoring system according to claim 120 ,wherein the first sensor is a pressure sensor.
 135. The monitoringsystem according to claim 120 , wherein the first sensor is associatedwith an item of equipment interconnected in the tubular string, andwherein the tool is permitted to displace a closure member of the itemof equipment to an open position only when predetermined acceptable datais transmitted from the first sensor via the first and second devices.136. The monitoring system according to claim 135 , wherein thepredetermined acceptable data indicates an acceptable pressuredifferential across the closure member.
 137. The monitoring systemaccording to claim 135 , wherein the tool is permitted to displace theclosure member to an equalizing position when the predeterminedacceptable data is not transmitted from the first sensor.
 138. Adownhole communication method, comprising the steps of: installing anitem of equipment in a tubular string in a subterranean well, the itemof equipment including a first communication device; conveying a toolinto the tubular string, the tool including a second communicationdevice; and establishing communication between the first and seconddevices.
 139. The method according to claim 138 , wherein the step ofestablishing communication is performed in response to positioning thesecond device in sufficiently close proximity to the first device. 140.The method according to claim 138 , further comprising the step ofsupplying power to the first device from the second device.
 141. Themethod according to claim 140 , wherein the supplying power step isperformed by transmitting waves from the second device to the firstdevice.
 142. The method according to claim 141 , wherein thetransmitting step is performed by the second device generatingelectromagnetic waves.
 143. The method according to claim 141 , whereinthe transmitting step is performed by the second device generatingpressure waves.
 144. The method according to claim 143 , wherein thegenerating step is performed by exciting at least one piezoelectriccrystal included in the second device.
 145. The method according toclaim 140 , wherein the supplying power step is performed by inductivecoupling between the first and second devices.
 146. The method accordingto claim 140 , wherein the supplying power step is performed by directelectrical contact between the first and second devices.
 147. The methodaccording to claim 138 , wherein the establishing communication stepfurther includes activating the first device from a dormant state to anactive state.
 148. The method according to claim 147 , whereinperformance of the activating step permits communication between thefirst and second devices.
 149. The method according to claim 138 ,further comprising the step of utilizing the communication between thefirst and second devices to determine when the tool is within apredetermined distance of an operative position of the tool relative tothe item of equipment.
 150. The method according to claim 138 , furthercomprising the step of the first device communicating to the seconddevice an indication that the tool is operatively positioned relative tothe item of equipment.
 151. The method according to claim 138 , furthercomprising the step of utilizing the communication between the first andsecond devices to indicate that an engagement member of the tool isaligned with a profile of the item of equipment.
 152. The methodaccording to claim 151 , further comprising the step of permitting thetool to displace the engagement member into engagement with the profilein response to the indication that the engagement member is aligned withthe profile.
 153. The method according to claim 138 , further comprisingthe step of communicating data indicative of a status of the item ofequipment from the first device to the second device.
 154. The methodaccording to claim 153 , wherein in the communicating step, the item ofequipment is a valve, and the status is a position of a closure memberof the valve.
 155. The method according to claim 153 , wherein in thecommunicating step, the item of equipment is a valve, and the status isa pressure applied to a closure member of the valve.
 156. The methodaccording to claim 153 , wherein in the communicating step, the item ofequipment is a valve, and the status is a pressure differential across aclosure member of the valve.
 157. The method according to claim 153 ,wherein in the communicating step, the item of equipment is a portion ofthe tubular string, and the status is a pressure applied to the tubularstring portion.
 158. The method according to claim 153 , wherein in thecommunicating step, the item of equipment is a portion of the tubularstring, and the status is a strain in the tubular string portion. 159.The method according to claim 153 , wherein in the communicating step,the item of equipment is a portion of the tubular string, and the statusis a pressure differential across the tubular string portion.
 160. Themethod according to claim 153 , wherein in the communicating step, theitem of equipment is a packer, and the status is a pressure applied tothe packer.
 161. The method according to claim 153 , wherein in thecommunicating step, the item of equipment is a packer, and the status isa pressure differential across the packer.
 162. The method according toclaim 153 , wherein in the communicating step, the item of equipment isa packer, and the status is a position of a seal assembly relative tothe packer.
 163. The method according to claim 153 , wherein in thecommunicating step, the item of equipment is a packer, and the status isa hardness of a seal member of the packer.
 164. The method according toclaim 163 , further comprising the step of determining the seal memberhardness by inducing vibration of the seal member.
 165. The methodaccording to claim 164 , wherein the determining step further comprisesmeasuring a resonant frequency of the seal member.
 166. The methodaccording to claim 153 , wherein in the communicating step, the item ofequipment is a packer, and the status is a compression in a seal memberof the packer.
 167. The method according to claim 153 , wherein in thecommunicating step, the item of equipment is a packer, and the status isa temperature of a seal member of the packer.
 168. The method accordingto claim 153 , wherein in the communicating step, the item of equipmentis a packer, and the status is a strain in a seal member of the packer.169. The method according to claim 153 , wherein in the communicatingstep, the item of equipment is a packer, and the status is a resistivityof a seal member of the packer.
 170. The method according to claim 153 ,wherein in the communicating step, the item of equipment is a plugsystem, and the status is a pressure applied to a closure member of theplug system.
 171. The method according to claim 153 , wherein in thecommunicating step, the item of equipment is a plug system, and thestatus is a pressure differential across a closure member of the plugsystem.
 172. The method according to claim 153 , wherein in thecommunicating step, the item of equipment is a plug system, and thestatus is a pressure differential across a plug assembly of the plugsystem.
 173. The method according to claim 153 , wherein in thecommunicating step, the item of equipment is a plug system, and thestatus is a pressure differential across an equalizing member of theplug system.
 174. The method according to claim 138 , further comprisingthe step of controlling operation of the tool at least in part inresponse to data communication from the first device to the seconddevice.
 175. The method according to claim 174 , wherein the item ofequipment is a valve having a closure member, and wherein thecontrolling step further comprises restricting the tool from displacingthe closure member at least in part in response to data communicatedfrom the first device to the second device.
 176. The method according toclaim 174 , wherein the item of equipment is a plug system having anequalizing member, and wherein the controlling step further comprisesrestricting the tool from displacing the equalizing member at least inpart in response to data communicated from the first device to thesecond device.
 177. The method according to claim 138 , wherein theinstalling step further comprises remotely positioning the first devicerelative to the remainder of the item of equipment.
 178. The methodaccording to claim 138 , further comprising the step of transmittingfrom the tool to a remote location data communicated from the firstdevice to the second device.
 179. The method according to claim 138 ,further comprising the step of connecting the first device to a sensorincluding a power source.
 180. The method according to claim 179 ,further comprising the step of supplying power to operate the firstdevice from the sensor power source.
 181. A particle detection system,comprising: a tubular member interconnected in a tubular string; aparticle sensor configured for detecting flow of particles through thetubular member; a first communication device connected to the particlesensor; and a tool received in the tubular string, the tool including asecond communication device, and communication being established betweenthe first and second devices.
 182. The system according to claim 181 ,further comprising a memory device interconnected to the sensor. 183.The system according to claim 182 , wherein the memory device storesindications of particle flow through the tubular member as detected bythe sensor.
 184. The system according to claim 182 , wherein the memorydevice is connected to the first communication device.
 185. The systemaccording to claim 184 , wherein data is transferred from the memorydevice to the tool when the first communication device communicates withthe second communication device.
 186. The system according to claim 181, wherein indications of particle flow through the tubular member aretransferred directly from the particle sensor to the tool 206 via thefirst and second communication devices in real time.
 187. The systemaccording to claim 181 , wherein the first and second communicationdevices communicate via direct electrical contact.
 188. The systemaccording to claim 181 , wherein the second communication devicesupplies power to the first communication device, thereby permitting thefirst device to communicate with the second device.
 189. The systemaccording to claim 188 , wherein the power is supplied byelectromagnetic waves emanating from the second device.
 190. The systemaccording to claim 189 , wherein the electromagnetic waves are radiofrequency waves.
 191. The system according to claim 188 , wherein thepower is supplied by pressure pulses emanating from the second device.192. The system according to claim 191 , wherein the pressure pulses areacoustic waves.
 193. The system according to claim 188 , wherein thepower is supplied by direct electrical contact between the first andsecond devices.
 194. The system according to claim 188 , wherein thepower is supplied by inductive coupling between the first and seconddevices.
 195. The system according to claim 181 , wherein the seconddevice activates the first device from a dormant state to an activestate, thereby permitting communication between the first and seconddevices.
 196. The system according to claim 195 , wherein thecommunication between the first and second devices is viaelectromagnetic waves.
 197. The system according to claim 196 , whereinthe electromagnetic waves are radio frequency waves.
 198. The systemaccording to claim 195 , wherein the communication between the first andsecond devices is via pressure pulses.
 199. The system according toclaim 198 , wherein the pressure pulses are acoustic waves.
 200. Thesystem according to claim 195 , wherein the communication between thefirst and second devices is via inductive coupling between the first andsecond devices.
 201. The system according to claim 181 , wherein thecommunication between the first and second devices indicates when thetoot is within a predetermined distance of an operative position of thetool relative to the item of equipment.
 202. The system according toclaim 201 , wherein the first device communicates to the second devicethat the tool is operatively positioned relative to the item ofequipment.
 203. The system according to claim 181 , wherein the particlesensor detects particle flow axially through the tubular member. 204.The system according to claim 181 , wherein the particle sensor detectsparticle flow through a sidewall of the tubular member.